I think the first question we should ask ourselves is whether to open-source it or not (or maybe open-source it in alpha and close it later, like Desktop Dungeons).
For purely closed-source things, the "license" doesn't really matter, it can just be the standard "use at your own risk and don't rip us off" disclaimer.
For dual-licensed things, the norm is something less permissive for commercial applications, like the GPL. I'm not sure it makes any sense to dual-license a game, though. You usually see dual licensing with things like libraries... use it in your OSS product freely under the OSS license (with paid support maybe), use in your commercial project and pay us for a license.
For purely open source things, I'm a big fan of the MIT license. It's very to-the-pont and permissive.
The MIT License (MIT)
Copyright (c) <year> <copyright holders>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.